I found numerous negative volumes as one can see at the picture.
It happens with most rotor blade grids (with fillets at hubs and without shroud tips yet), stator vanes cause no problems.
I coped with it every time but once just changing automatic ATM topology to single round round refined method and back to automatic and negative volume elements disappeared, but not this time.
Bias of blade towards high periodic changed nothing.
How can I deal with it? Why this layer is so close to the blade and what cause these elements?